In batteries, the anode and cathode are separated from one another by a separator membrane. Today, “lithium batteries” are very popular because they are able to generate high energy outputs. The lithium battery market can be divided into two groups, the “primary” lithium battery and the “secondary” lithium battery. The primary lithium battery is a non-rechargeable or disposable battery, while the secondary lithium battery is a rechargeable battery.
In batteries, thin battery separators can provide several advantages that can improve the battery's performance and design. First, thinner separators enable attainment of higher rate capabilities. This means that the battery is able to produce higher current densities across the membrane because the electrical resistance of the separator can be reduced by reducing the separator's thickness. For a correlation of Gurley value to electrical resistance: see generally, Callahan, R. W. et al, “Characterization of Microporous Membrane Separators,” Mar. 1-4, 1993 delivered at the Tenth International Seminar on Primary and Secondary Battery Technology and Application sponsored by Florida Educational Seminars, Inc., 2836 Banyon Blvd. Circle N.W., Boca Raton, Fla. 33431. The higher rate capabilities are important where quick power is needed (e.g., for acceleration in an electric vehicle). Second, thinner separators allow the use of thinner electrodes. This means that the battery may attain better electrode utilization and electrode cycling. The electrode utilization means that smaller batteries with equivalent power can be produced. The better electrode cycling means a greater number of rechargings or cycles over the battery's life. Third, thinner separators allow greater choice in separator design. In other words, various thin separators can be combined to custom design a separator for a particular battery.
Accordingly, there is a need in the battery arts for thinner battery separators, for thinner performing battery separators, for optimized, new or improved battery separators for certain applications or batteries, for optimized, new or improved ultra thin battery separators, for optimized, new or improved coated battery separators, and/or the like.